Ionization deposition apparatus

Abstract

An ionization deposition apparatus includes an ion source which is located in a vacuum chamber and which is provided with gas introduction ports for supplying a gaseous film material into the vacuum chamber, a filament unit, which is separated into a plurality of independently controllable filaments, for generating thermoelectrons when the filaments are heated by filament currents, and an anode electrode for accelerating and colliding the thermoelectrons against molecules of the gaseous film material to thereby turn the molecules to plasma. A holder for holding a to-be-deposited object, the holder being placed confronting the anode electrode of the ion source in the vacuum chamber, and connected to a bias source to attract ions in the plasma to a surface of the holder.

What is claimed is: 
     
       1. An ionization deposition apparatus which comprises: an ion source which is located in a vacuum chamber, said ion source including (1) gas introduction ports for supplying a gaseous film material into the vacuum chamber, (2) a filament unit, which includes a plurality of independent filaments for which respective current amounts of filament currents flowing in said filaments are independently controlled, for generating thermoelectrons when the filaments are heated by the filament currents, and an (3) anode electrode for accelerating and colliding the thermoelectrons against molecules of the gaseous film material to turn the molecules to plasma;   a holder for holding a to-be-deposited object, the holder being placed confronting to the anode electrode of the ion source in the vacuum chamber, and connected to a bias source to attract ions in the plasma to a surface of the holder;   a bias current detector for detecting a bias current of said bias source; and   a control unit for changing a ratio of all the filament currents so as to maintain the detected bias current constant.   
     
     
       2. The ionization deposition apparatus according to claim 1, wherein said control unit controls the filament currents so as to maintain the bias current flowing in the bias source constant. 
     
     
       3. The ionization deposition apparatus according to claim 2, wherein the control unit controls the filament currents so that the filament currents flowing in the filaments initially have preset values and then a ratio of all the filament currents is varied so as to maintain the bias current flowing in the bias source constant. 
     
     
       4. The ionization deposition apparatus according to claim 1, further comprising a cooling unit for cooling the holder. 
     
     
       5. The ionization deposition apparatus according to claim 1, further comprising a driving device for rotating the holder about its axis. 
     
     
       6. An ionization deposition apparatus which comprises: an ion source which is located in a vacuum chamber, said ion source including (1) gas introduction ports for supplying a gaseous film material into the vacuum chamber, (2) a filament unit, which includes a plurality of independent filaments for which respective current amounts of filament currents flowing in said filaments are independently controlled, for generating thermoelectrons when the filaments are heated by the filament currents, and an (3) anode electrode for accelerating and colliding the thermoelectrons against molecules of the gaseous film material to turn the molecules to plasma;   a holder for holding a to-be-deposited object, the holder being placed confronting the anode electrode of the ion source in the vacuum chamber, and connected to a bias source to attract ions in the plasma to a surface of the holder;   a bias current detector for detecting a bias current of said bias source;   a control unit for changing a ratio of all of the filament currents so as to maintain the detected bias current constant; and   a circulating unit contained within said holder for circulating a coolant fluid within said holder, said circulating unit including an inner fluid cavity extending lengthwise within said holder and coupled to a fluid inlet, an outer fluid cavity extending lengthwise within said holder surrounding said inner fluid cavity and coupled to a fluid outlet, and a plurality of fluid openings extending between said inner fluid cavity and said outer fluid cavity.